School of Animal Biology, University of Western Australia, Crawley, WA, Australia. krobert @ cyllene.uwa.edu.au
Sex Dev. 2010;4(1-2):119-28. doi: 10.1159/000260373. Epub 2009 Nov 20.
Although temperature-dependent sex determination (TSD) has been a 'hot topic' for well over 30 years, the discovery of TSD in viviparous taxa is recent. Viviparity and TSD was regarded unlikely on theoretical grounds as viviparity allows for high stable developmental temperatures through maternal basking. However, pregnant squamates of many species choose different body temperatures from non-pregnant females and males, and we now know that differential temperature selection by viviparous species with TSD allows for the production of sons or daughters. Three species of squamate reptiles (all are skinks) are now know to exhibit TSD. The physiological mechanism by which viviparous reptiles control the sex of their offspring is not understood, but exposure to different operational sex ratios in the adult population is a factor in some species. The functional role of sex steroid hormones in egg yolk and how the hormones are manipulated in utero is still an area requiring detailed investigation. Fast maturing squamate reptiles provide an excellent, but as yet underutilized, model system for studying the adaptive significance of TSD, and the occurrence of TSD in viviparous species requires substantially more work on a phylogenetically diverse range of species.
尽管温度依赖型性别决定（TSD）已经成为一个“热门话题”超过 30 年，但最近才发现胎生动物中的 TSD。胎生和 TSD 在理论上被认为不太可能，因为胎生允许通过母体晒热来维持高稳定的发育温度。然而，许多种蜥蜴类爬行动物的怀孕个体选择与非怀孕雌性和雄性不同的体温，我们现在知道，具有 TSD 的胎生物种通过不同的温度选择可以产生雄性或雌性后代。现在已知有三种蜥蜴类爬行动物（均为石龙子）表现出 TSD。胎生爬行动物控制其后代性别的生理机制尚不清楚，但在某些物种中，成年群体中不同的有效性别比例是一个因素。性类固醇激素在蛋黄中的功能作用以及激素在子宫内如何被操纵仍然是一个需要详细研究的领域。快速成熟的蜥蜴类爬行动物提供了一个极好的但尚未充分利用的模型系统，用于研究 TSD 的适应意义，而胎生物种中 TSD 的发生需要在更广泛的物种范围内进行更多的研究。
